Chromatograph, and sample analysis method

Abstract

A liquid analysis device (HPLC device) includes a main flow path provided with a first buffer portion, a first switch valve, an HPLC column, a second switch valve, and a second buffer portion; and a bypass flow path that bypasses the HPLC column. A controller, by controlling a pump, the first switch valve, and the second switch valve, switches between a first path that allows at least a portion of a fluid held in the first buffer portion to flow into the second buffer portion through the main flow path and a second path that allows a fluid held in the second buffer portion to flow into the first buffer portion through the bypass flow path spanning between the first switch valve and the second switch valve in the main flow path.

1 . A chromatograph, comprising:
 a pump configured to send out a fluid including a sample, the sample being a liquid or a gas;   a column configured to receive the fluid therein and separate components of the sample through interaction between the sample and a stationary phase held inside the column;   a main flow path provided with, from one end side to an opposite end side, a first buffer portion, a first switch valve, the column, a second switch valve, and a second buffer portion;   a bypass flow path connected between the first switch valve and the second switch valve such that the bypass flow path bypasses the column;   a detector configured to detect the components separated by the column; and   a control unit configured to control the pump, the first switch valve, and the second switch valve, the control unit configured to
 switch a flow path between the first switch valve and the second switch valve in the main flow path to the bypass flow path by switching the first switch valve and the second switch valve, and 
 control the pump, the first switch valve, and the second switch valve, and switch between a first path and a second path, the first path allowing at least a portion of the fluid held in the first buffer portion to flow into the second buffer portion through the main flow path, the second path allowing the fluid held in the second buffer portion to flow into the first buffer portion through the bypass flow path spanning between the first switch valve and the second switch valve in the main flow path. 
   
     
     
         2 . The chromatograph according to  claim 1 , wherein the detector is disposed in the main flow path. 
     
     
         3 . The chromatograph according to  claim 2 , wherein the detector is disposed between the column and the second switch valve. 
     
     
         4 . The chromatograph according to  claim 1 , wherein the detector is disposed outside the main flow path and the bypass flow path. 
     
     
         5 . The chromatograph according to  claim 4 , further comprising:
 a discharge flow path configured to discharge the fluid from a downstream side of the second buffer portion in the first path, wherein   the detector is disposed in the discharge flow path.   
     
     
         6 . The chromatograph according to  claim 4 , further comprising:
 a discharge flow path configured to discharge the fluid from between the column and the second buffer portion in the first path, wherein   the detector is disposed in the discharge flow path.   
     
     
         7 . The chromatograph according to  claim 4 , further comprising:
 a second bypass flow path connected between the first switch valve and the second switch valve such that the second bypass flow path bypasses the column, wherein   the detector is disposed in the second bypass flow path.   
     
     
         8 . The chromatograph according to  claim 1 , further comprising:
 a sample collecting flow path configured to collect the sample stored in a sample tank; and   a mobile phase medium flow path configured to collect a mobile phase medium stored in a mobile phase medium tank, wherein   one end of the sample collecting flow path and one end of the mobile phase medium flow path are connected to the first switch valve,   the pump is disposed upstream from the first buffer portion in the first path, and   the control unit is configured to switch between injection of the sample and injection of the mobile phase medium into the first buffer portion by controlling the pump and the first switch valve.   
     
     
         9 . The chromatograph according to  claim 1 , wherein the first buffer portion and the second buffer portion are each a pipe conduit having a predetermined volume. 
     
     
         10 . The chromatograph according to  claim 9 , wherein the predetermined volume is a capacity no smaller than a fluid amount necessary for the column to separate the components. 
     
     
         11 . A sample analysis method for use in a chromatograph that includes
 a pump configured to send out a fluid including a sample, the sample being a liquid or a gas,   a column configured to receive the fluid therein and separate components of the sample through interaction between the sample and a stationary phase held inside the column,   a main flow path provided with, from one end side to an opposite end side, a first buffer portion, a first switch valve, the column, a second switch valve, and a second buffer portion,   a bypass flow path connected between the first switch valve and the second switch valve such that the bypass flow path bypasses the column, and   a detector configured to detect the components separated by the column,   the sample analysis method comprising:   a separation step of supplying at least a portion of the fluid held in the first buffer portion to the column via the first switch valve in the main flow path such that the column separates the components of the sample;   a holding step of supplying the fluid that has passed through the column to the second buffer portion via the second switch valve in the main flow path and holding the fluid in the second buffer portion;   a collection step of controlling the first switch valve and the second switch valve, switching a flow path between the first switch valve and the second switch valve in the main flow path to the bypass flow path and returning the fluid held in the second buffer portion to the first buffer portion via, sequentially, the second switch valve and the first switch valve with the fluid bypassing the column; and   a detection step of repeating the separation step, the holding step, and the collection step and performing detection by the detector after at least the separation step has been performed N times (N is an integer greater than 1),   the separation step of an nth instance (n is an integer satisfying 1≤n≤N) including supplying the fluid from the first buffer portion to the column in a fluid amount n times a fluid amount necessary for the column to separate the components in the separation step of a first instance.   
     
     
         12 . The sample analysis method according to  claim 11 , wherein the detection step includes performing the detection by the detector each time the separation step is performed. 
     
     
         13 . The sample analysis method according to  claim 11 , wherein the detection step includes performing the detection by the detector only after the separation step of an Nth instance. 
     
     
         14 . The sample analysis method according to  claim 11 , wherein the detection step includes performing the detection by the detector after the separation step of an mth instance (m is an integer satisfying 1≤m<N).